Book Image

Computer Programming for Absolute Beginners

By : Joakim Wassberg
4 (1)
Book Image

Computer Programming for Absolute Beginners

4 (1)
By: Joakim Wassberg

Overview of this book

Learning how to code has many advantages, and gaining the right programming skills can have a massive impact on what you can do with your current skill set and the way you advance in your career. This book will be your guide to learning computer programming easily, helping you overcome the difficulties in understanding the major constructs in any mainstream programming language. Computer Programming for Absolute Beginners starts by taking you through the building blocks of any programming language with thorough explanations and relevant examples in pseudocode. You'll understand the relationship between computer programs and programming languages and how code is executed on the computer. The book then focuses on the different types of applications that you can create with your programming knowledge. You'll delve into programming constructs, learning all about statements, operators, variables, and data types. As you advance, you'll see how to control the flow of your programs using control structures and reuse your code using functions. Finally, you'll explore best practices that will help you write code like a pro. By the end of this book, you'll be prepared to learn any programming language and take control of your career by adding coding to your skill set.
Table of Contents (19 chapters)
1
Section 1: Introduction to Computer Programs and Computer Programming
6
Section 2: Constructs of a Programming Language
7
Chapter 5: Sequence – The Basic Building Block of a Computer Program
14
Section 3: Best Practices for Writing High-Quality Code
Appendix B: Dictionary
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
R
S
T
U
V
W

Local and global variables

A variable declared (created) inside a function is called a local variable, and it can only be accessed from within the function. Outside the function, it is as if the variable never existed at all. Check the following code:

function my_function()
    name = "Lisa"
end_function
my_function()
print name

Here, we create and assign a value to the name variable inside the my_function function. Outside the function, we first call the function, and then we try to print the name. The program will crash with an error on the line where we try to print the name. The reason is that the name variable is unknown in this part of the program. It is only valid as long as we execute code inside the function.

This is a local variable. It is local as it is created inside the function.

If we instead change the program so it looks like this, things will be different:

name = "Bill"
function my_function()
   ...